GB1604334A - Photographic film feed mechamism for a camera - Google Patents

Description

PATENT SPECIFICATION

Application No 38502/80 Divided out of No 1 604 333 Convention Application No.

52/069725 ( 11) ( 22) Filed 25 May 1978 ( 32) Filed 13 June 1977 in Japan (JP) Complete Specification published 9 Dec 1981

INT CL 3 G 03 B 1/08 17/42 Index at acceptance G 2 A 210217 C 1 MC ( 54) PHOTOGRAPHIC FILM FEED MECHANISM FOR A CAMERA ( 71) We, ASAHI KOGA Ku Ko G Yo KABUSHIKI KAISHA, a Japanese Company of 36-9 Maeno-cho, 2-chome, Itabashi-ku, Tokyo, Japan, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to a feed mechanism for feeding photographic film which is housed in a cassette.

In cameras which use photographic film housed in a cassette, it has been customary to dispose a film winding shaft of a camera in the vicinity of a winding spool of the cassette In some cases it is, however, recommended that the film winding shaft is disposed on the opposite side of the winding spool from the viewpoint of ease of operation If in such cases the film winding shaft is arranged to effect a reciprocating motion, it is possible to rotate a spool gear by means ot a rack or the like However, if the film winding shaft is designed so as to be rotatable in one direction only, it has previously been necessary to provide a complicated transmission mechanism, such as two pairs of helical gears positioned crosswise.

It is an object of the present invention to obviate or mitigate this difficulty.

According to the present invention, there is provided a feed mechanism for feeding photographic film which is housed in a cassette, the feed mechanism comprising rotatable winding means, a control member operatively coupled to the winding means and arranged to be rotated thereby in one direction only, a link coupled to the control member so that rotation of the control member is converted to reciprocatory movement of the link, and a gear engageable with a spool of said cassette, the gear being coupled to the link through a one-way clutch so that reciprocation of the link causes intermittent unidirectional rotation of the gear to wind on said film.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, in which:Figure 1 is a diagrammatic view of a photographic film feed mechanism according to the present invention, the feed mechanism being shown after a picture 55 taking operation has been completed, and before the film has been wound on; and Figure 2 is a similar view to Figure 1, showing the feed mechanism immediately after winding on of the film has been stop 60 ped.

Referring to Figures 1 and 2, shown at 1 is a gear which is directly coupled to a winding shaft adapted to rotate through a given angle in one direction alone (in the direction 65 of the arrow), and which is in mesh with a gear 4 by way of a setting gear 2 having an upright pin 3 thereon Mounted on a common shaft with the gear 4 is a film-feed control disc 5 having a series of circumferential 70 stop teeth Sa The control disc 5 is coupled by means of a shaft 6 to one end of a link 7, the other end of the link being coupled by means of a shaft 8 to a bell crank 9 The bell crank 9 is, in turn, mounted on a shaft 9 a on 75 which is also mounted a drive gear 12 By the co-operation of a pawl 10 connected by means of a shaft 9 b to bell crank 9 and a spring 11 which interconnects the bell crank 9 and the pawl 10 and which biases the 80 pawl 10 against the drive gear 12, bell crank 9 and drive gear 12 constitute a one-way clutch A gear 13 is connected directly to the drive gear 12 and is operatively coupled to a spool gear 17 provided in a cassette by way 85 of further gears 14, 15 and 16 Designated at 18 is a spring which acts on the gear 13 to prevent reverse rotation of the latter.

A photographic film 30 housed in the cassette is advanced by a predetermined 90 amount by rotation of the control disc 5.

Since the degree of rotation of control disc 5 is dependent on the amount of film being wound on the spool, it is preferable that a slip mechanism is provided between the 95 gear 4 (which rotates in only one direction) and the control disc 5.

Shown at 19 is a setting lever which is pivotally mounted on a shaft 19 a The lever 19 at one end has a bent portion 19 b which 100 m ( 62) A, { 31} 1-Z { 433} re ( 44 51} { 525 1604334 1 604 334 is adapted to engage the setting pin 3 and at the other end has an arm 19 c which is adapted to engage a mirror setting lever or shutter setting lever 20 A stop lever 21 for stopping the film winding operation is rotatable about a shaft 21 a and has an end portion 21 b adapted to extend into or retract from the path of movement of the setting p in 3, and a spring 22 biases the stop lever 21 in a clockwise direction A film stopping lever 23 is rotatable about a shaft 23 a and at one end thereof has a pawl 23 d which is adapted to engage the stop teeth 5 a on the control disc 5 At the other end thereof, the lever 23 has a pin 23 b and a further pin 23 c which is positioned in the path of movement of both the stop lever 21 and the setting lever 19.

An operating lever 24 is rotatable about a shaft 24 a and at one end thereof has a forked portion 24 b which receives the pin 23 b, and at the other end thereof has an end portion 24 d and a projection 24 c The operating lever 24 is biased counterclockwise by a spring 24 c towards a rest position.

A locking lever 25 rotatable about a shaft a has a stepped portion which is engageable with the bent portion 24 c of the operating lever 24, and is biased clockwise by a spring (not shown) towards a locking position A detection pawl 26 is rotatable and slidable relative to a pin 27 and has a projection 26 a which is opposed to the end portion 24 d of the operating lever 24 and a bent portion 26 b which is opposed to a side edge of the locking lever 25 The detection pawl 26 is coupled by a spring 28 to the bent portion 24 c of the operating lever 24, and is thereby biased to slide upwards as well as to rotate clockwise Such rotation of the detection pawl 26 is limited by a fixed stop 29 so that it can engage the perforations in the film in turn as the latter approach a predetermined position.

Operation of the film feeding mechanism will now be described Figure 1 shows the mechanism in a condition wherein a picture-taking operation has just terminated Simultaneously with the completion of the picture-taking operation, the shutter or mirror setting member 20 is returned upwards (as viewed in the drawings) and thereby rotates the setting lever 19 clockwise.

Engagement of the lever 19 with the pin 23 c causes the lever 23 to rotate counterclockwise, and engagement of the pin 23 c with the lever 21 in turn causes the latter to rotate clockwise also At the same time, the operating lever 24 is rotated clockwise out of its rest position by way of the pin 23 b, and as a consequence the projection 24 c on the operating lever 24 is engaged by the stepped portion of locking lever 25, so that the locking lever 25 now in its locking position retains the operating lever 24 away from its rest position The detection pawl 26 is urged upwards (as viewed in the drawings) by the force of the spring 28 while being in contact with stop 29, and is brought into resilient contact with the film 30 Under 70 this situation, the end portion 21 b of the lever 21 assumes a position retracted from the path of movement of the pin 3, and the pawl 23 d and the lever 23 assumes a position retracted from the stop teeth 5 a, so that 75 the setting gear 2 and the control disc 5 are free to rotate.

Upon rotation of the winding gear 1 in the direction of the arrow, the pin 3 engages the bent portion 19 b of the lever 19 and rotates 80 the lever 19 counterclockwise thereby moving the shutter or mirror setting lever 20 to a lower position (as viewed in the drawings).

At the same time, the control disc 5 is rotated in the direction of the arrow, with 85 the shaft 6 moving in the direction of the arrow to assume positions 6 ' and 6 " successively Rotation of the control disc 5 is thereby converted to reciprocating movement of the link 7, and this reciprocating 90 movement is in turn transmitted inter alia by way of the bell crank 9 and the drive gear 12 to the film spool gear 17 The gear 17 is thus rotated intermittently and unidirectionally, thereby moving the film 30 in the direction 95 of the arrow.

As one of the perforations in the film approaches a predetermined position it is engaged by the detection pawl 26 and the latter moves in a direction generally per 100 pendicular to the direction of film travel to such an extent that the projection 26 a comes into contact with the arm 24 d of the operating lever 24 As the perforation moves into said predetermined position 105 upon further movement of the film, the detection pawl 26 is rotated counterclockwise and assumes a biased position shown at 26 ' in Figure 1 At this instant, the bent portion 26 b of the detection pawl 26 urges the 110 locking lever 25 counterclockwise out of its locking position, thereby disengaging the projection 24 c on the operating lever 24 from the stepped portion of the locking lever 25 The operating lever 24 is thus 115 released and rotates counterclockwise into its rest position under the bias of the spring 24 c By virtue of the engagement of the end portion 24 d of the lever 24 with the projection 26 a, the detection pawl 26 is thereby 120 disengaged from the perforation in a direction substantially perpendicular to the direction of film travel, and is then urged clockwise by the spring 28 and into engagement with the stop 29, as shown in Figure 2 125 Simultaneously with this movement, the lever 23 is turned clockwise by virtue of the engagement between the forked portion 24 b and the pin 23 b, bringing the pawl 23 d into engagement with one of the stop teeth 130 1 604 334 a to interrupt rotation of control disc 5, thereby halting the feeding of the film At the same time, the lever 21 is turned by way of pin 23 c under the action of the spring 22, thereby positioning the end portion 21 b in the path of movement of the pin 3 At this time, by virtue of the action of the abovementioned slip mechanism the gear 4 remains free to rotate whereas the winding gear 1 and the setting gear 2 continue to rotate only until the pin 3 reaches the position 3 ' in which it engages the end portion 21 b of the lever 21, during which time the setting lever 19 is moved counterclockwise.

During such counterclockwise movement of the setting lever 19, the shutter setting or mirror setting lever 20 is urged to a position ', thereby terminating the setting operation.

From the above description it will be manifest that, when a perforation arrives at a predetermined position, the detection pawl 26 disengages from the perforation and feeding of the film is stopped Since the film is maintained free from any force, undesired shifting of the film is avoided Furthermore, unidirectional rotation of the control disc 5 coupled to the winding gear is converted by means of the link 7 to a reciprocating movement This reciprocating movement is transmitted by way of the one-way clutch to the film spool, thereby driving it intermittently, and when a perforation arrives at a predetermined position feeding of the film is stopped Such an arrangement eliminates the need to provide a complicated transmission mechanism as well as to limit the position of the winding operation member to the vicinity of the film spool, but such a winding member as in the present invention is permitted to be positioned on the opposite side of the spool without impairing the operability of the mechanism This provides a greatly increased freedom in design of the film winding mechanism 45 The film feed mechanism described above also forms the subject of our co-pending UK Patent Application No 22264/78 (Serial No 1 604 333) of even date.

Claims (3)

WHAT WE CLAIM IS: 50

1 A feed mechanism for feeding photographic film which is housed in a cassette, the feed mechanism comprising rotatable winding means, a member operatively coupled to the winding means and arranged to 55 be rotated thereby in one direction only, a link coupled to the control member so that rotation of the control member is converted to reciprocatory movement of the link, and a gear engageable with a spool of said cas 60 sette, the gear being coupled to the link through a one-way clutch so that reciprocation of the link causes intermittent unidirectional rotation of the gear to wind on said film 65

2 A feed mechanism as claimed in Claim 1, wherein the one-way clutch comprises a pivotable lever to which the link is connected and a pawl mounted on the lever and engageable with ratchet teeth rotatable 70 with said gear.

3 A feed mechanism for feeding photographic film which is housed in a cassette, as claimed in Claim 1 and substantially as hereinbefore described with reference to the 75 accompanying drawing.

MARKS & CLERK, Alpha Tower, ATV Centre, Birmingham Bl l TT Agents for the Applicants.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981 Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A I AY, from which copies may be obtained.